Rotating Pins?

[ContractSoldier]

I have recently rebuilt my AR15 from It's original build which was a DPMS lower receiver with Model 1 Sales parts kit, to a carbine using parts from DPMS and Bushmaster.

Ever since i first built the gun, I've notice that the pins in the lower receiver for the fire control group (the Model 1 Sales lower parts kit are still on the rifle, i plan on replacing them with Bushmaster lower receiver parts), will turn every time i pull the trigger.

Will these pins rotating every time i pull the trigger wear out the holes in the lower receiver and should these pins rotating, stop rotating when i replace them with a better quality, Bushmaster lower parts kit?

Is it normal for these pins to rotate when the trigger is pulled?

[mkmckinley]

Ehh not really normal. The hammer and trigger should be slipping on the pins, not the pins in the receiver. Have you bought the bushmaster parts kit yet, because a Daniel Defense one from BCM might be a better option. It seems really unlikely that the holes in the receiver could be drilled too big, even at DPMS.

[PlatoCATM]

Don't waste your money on more shitty parts. In the even that you don't want to buy a whole LPK, just buy the pins @ http://www.gandrtactical.com/cgi-bin/commerce.cgi?preadd=action&key=GRT-THP&reference=/cgi-bin/commerce.cgi%3Fsearch%3Daction%26keywords%3D%26searchstart%3D9%26template%3DPDGCommTemplates/FullNav/SearchResult.html%26category%3DGRTA

[m4fun]

This is not good - some rotaition is normal but unless I am misreading this, this seems quite extreme - follow the other guys advice on the parts kits - for grins strip the fcg out and see how easy to rotate pin in the hammer - try going back and fourth between pin for trigger and hammer and let us know there is a difference. Mind you, there is a "spring" in the hammer that is rides in the detent in the middle of the pin.

Let us know if you discover any "anomalies"

[ContractSoldier]

Everything seem's to be installed correctly, i think the Model 1 Sales lower receiver part's are out of spec. I never really cared to much for the Model 1 Sales parts, i was on a budget back then and when the AWB bill was no longer the law of the land, i started a rebuild project to convert it from a post ban A2, to a pre ban M4 style carbine.

Present setup includes the following:

DPMS M4 upper receiver
DPMS lower receiver
DPMS 14.5 inch chrome lined barrel with Bushmaster Phantom permanently welded and pinned on to BATF specs.
Bushmaster bolt carrier and assembly
DPMS M4 stock
Rock River arms M4 handguards
Model 1 Sales lower parts kit (from post ban build, haven't changed them yet)

Here's what i plan on doing to the rifle:

Change lower receiver parts with better brand

Put on a Magpul CTR stock and MAID grip set

Install Osprey Defense Piston

Change handguards over to RIS

[Artiz]

I'm in the same boat, I just built a stripped RRA lower receiver with an RRA LPK and the hammer pin rotates with the hammer.
Just wondering if it's normal, or am I worried over nothing.

EDIT: Corrected the problem myself, I put a drop of oil on each side of the hammer pin and manually cycled the hammer to make sure it's drowning real good, and it doesn't rotate anymore.

[ContractSoldier]

I'm in the same boat, I just built a stripped RRA lower receiver with an RRA LPK and the hammer pin rotates with the hammer.
Just wondering if it's normal, or am I worried over nothing.

EDIT: Corrected the problem myself, I put a drop of oil on each side of the hammer pin and manually cycled the hammer to make sure it's drowning real good, and it doesn't rotate anymore.

Good to hear that you got her fix, let's us know how she shoot's.

[markm]

How can you tell they're turning? Did you mark them?

Pin rotation is perfectly normal. If I manually cock the hammer in any lower I have the hammer pin will rotate with the hammer.

I have yet to see on legitimate case of pin hole elongation from pin rotation. :confused:

[Artiz]

Good to hear that you got her fix, let's us know how she shoot's.

I'm building her one piece at a time, money's tight like a virgin. :D

[ContractSoldier]

Lol, Artiz.

Markm, i can see the pin's turn, every time the trigger is pulled.

I've been looking at lower parts kit's, seem's like LMT are some of the best, but they are hard to find. Can anyone recommend the next best thing to LMT that's not more then $150.00?. I know one member recommend's Daniel Defense lower parts kit.

Also, since I'm going with a Osprey Defense piston, it will come with a bolt carrier, but not a bolt assembly. From the reading I've done here, I'm considering keeping the bushmaster bolt assembly as an emergency field back up and going with either an LMT bolt assembly or a BCM bolt assembly that has been MPI.

Which of the two are of better quality and has the LMT been MPI?

[markm]

Markm, i can see the pin's turn, every time the trigger is pulled.

Perfectly normal. If I pull my triggers with the hammer up or down I can watch the pin rotate in the lower.

[ContractSoldier]

Perfectly normal. If I pull my triggers with the hammer up or down I can watch the pin rotate in the lower.

Thanks for the info, I'm still going to replace the lower parts kit with a better brand since Model 1 Sales parts are crapy.

[Thomas M-4]

markm is right it is completely normal for the pin to turn.
G&R tactical sells a LPK that is supposed to be to notch.
It has been over a year since I have seen a LMT LPK.

[ContractSoldier]

markm is right it is completely normal for the pin to turn.
G&R tactical sells a LPK that is supposed to be to notch.
It has been over a year since I have seen a LMT LPK.

Thanks. Could you advise me of the brand name of those parts so i can find them on their site?

[Cincinnatus]

The only time pin rotation becomes a problem is if you do a lot of full auto fire, or if the pins are not just rotating but actually backing out of receiver. That is why KNS and others offer non-rotating pin sets to keep that from happening. If your pins are not backing out of receiver and you are not doing a high volume amount of shooting, you probably don't need to worry about it.

[Cincinnatus]

As for the LPK, get a CMT or RRA brand and you're good to go. Daniel Defense, as already mentioned, is top notch.

[Thomas M-4]

Thanks. Could you advise me of the brand name of those parts so i can find them on their site?
http://www.gandrtactical.com/cgi-bin/commerce.cgi?preadd=action&key=GRT-LPK&reference=/cgi-bin/commerce.cgi%3Fsearch%3Daction%26keywords%3Dkits%26searchstart%3D0%26template%3DPDGCommTemplates/FullNav/SearchResult.html

Sold out right now :(

I think they are cherry picked from different manufactures but don't hold my feet to the fire on that;) Lot of good reviews on them.

[The_Biased_Observer]

http://i287.photobucket.com/albums/ll130/ArizonaK9/th_MOV00389.jpg (http://s287.photobucket.com/albums/ll130/ArizonaK9/?action=view&current=MOV00389.flv)

[Iraqgunz]

I am not trying to be an asshole here. KNS pins and their reputed value have been discussed many times over. They are a waste of money and really serve no purpose other than piece of mind. Tearing apart your lower incorrectly and ****ing up the holes with shit that shouldn't be poked in there will cause more damage then pins rotating.

[Iraqgunz]

Please explain why this doesn't seem to be an issue in the military when firing burst or auto? I have seen and fired M16's that were VERY old and many rounds put through them.

Pins will not back out of the receiver if the parts are not worn. If you have a worn or damaged "J" spring in the hammer or a worn or incorrectly installed hammer spring then of course it can happen.


The only time pin rotation becomes a problem is if you do a lot of full auto fire, or if the pins are not just rotating but actually backing out of receiver. That is why KNS and others offer non-rotating pin sets to keep that from happening. If your pins are not backing out of receiver and you are not doing a high volume amount of shooting, you probably don't need to worry about it.

[Cincinnatus]

Gunz, you have some good points. The KNS pins are more for piece of mind than any real need.
As for rifles in the military, unless you're in a special unit or in combat where you can fire any damn way you please, burst and full auto fire are usually not allowed--at least, in my experience they are not. Some things may have changed since I was in (10 years ago), but I remember having my ass handed to me for switching to burst during a live fire excercise, and the only time most guys I knew ever got to even try burst was if they switched it over during night fires when everybody and their dog was shooting and the NCOs wouldn't notice. Even so, firing on fullauto, IMHO, probably would not actually cause discernible wear on receiver holes unless one did this without lube and on a regular basis.
Whether there is actually a NEED for anti-rotation pins or not, both in general and in the situation of the OP, to answer the OP's original posts, that is ostensibly the PURPOSE of them. In the end, the "problem" of rotating pins is probably a nonexistent problem, or in other words, an invisible river and KNS is coming in to build an invisible bridge over it to make some dough. :)

[hoveyh]

This is probably a dead thread but I will offer my comments .....Others here with real life experience have posted this being a none issue and I can take it to heart and rest easy. I have two seperate builds using completely different lowers and LPK's and the pins rotated on both lowers from day one. I also have a box stock 6450 and the pins rotate in that as well.

Train, Shoot often and do your PM ..... rest easy.


H

[markm]

Gunz, you have some good points. The KNS pins are more for piece of mind than any real need.

People often say the KNS pins are cheap insurance.

I counter that with an offer to sell them a magic potion that will accomplish the EXACT same protection that KNS pins will. My potions are cheap insurance. :rolleyes: